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What is EPI or Exocrine Pancreatic Insufficiency?

Exocrine Pancreatic Insufficiency

What is EPI?

Exocrine pancreatic insufficiency, or EPI, refers to failure of the pancreas to normally secrete digestive enzymes. This results in diarrhea and weight loss, often despite the fact that the animal's appetite has increased. While EPI occurs in both dogs and cats, the most common cause is different in each species. EPI in dogs is usually due to a condition called Pancreatic Acinar Atrophy, or PAA, but in cats it is most commonly due to end-stage pancreatitis.

What Does The Pancreas Normally Do?

The pancreas has 2 functional parts:

The Endocrine Secretes hormones like insulin and glucagon, which are essential for the metabolism of carbohydrates and regulate blood sugar.

The Exocrine Consists of units called acini that produce and secrete enzymes to help digest food.

With EPI, there is gradual wasting away of the acini. Clinical signs do not develop until most of the acini are gone. As dogs lose the ability to digest protein, symptoms such as weight loss despite an increased appetite and diarrhea will appear.

Can My Pet Get EPI?

While it is more common in dogs, cats can also be affected by EPI. Young adult dogs, especially German Shepherds, are most likely to be affected with PAA-associated exocrine pancreatic insufficiency. Older dogs and cats affected by EPI will usually develop the disease as a consequence of end-stage chronic pancreatitis.

How Does My Pet Get EPI?

Pancreatic acinar atrophy ( PAA), is the most common cause of exocrine pancreatic insufficiency in dogs. It is common in young adult dogs, but not recognized in cats. The cause for PAA is still not known.

End-stage inflammation of the pancreas, or pancreatitis, may also result in EPI. When this is the case, diabetes mellitus in dogs and cats may also be seen due to damage to the endocrine portion of the pancreas. Pancreatitis is more commonly the cause of EPI in cats and older dogs.

How is EPI Diagnosed?

Clinical Signs:

Clinical signs associated with exocrine pancreatic insufficiency include weight loss, polyphagia, coprophagia, pica, diarrhea, increased borborygmus, and flatulence. Routine diagnostic tests eliminate some of these as possibilities. Once EPI is suspected, there are specific laboratory tests that can be used for a diagnosis.

There are 3 major types of tests for EPI:

The Serum Trypsin-like Immunoreactivity Test A blood test is the biggest breakthrough in the diagnosis of Exocrine Pancreatic Insufficiency so far.

The Fecal Protease Test A stool sample is tested for protein digesting enzymes.

The Fecal Elastase Test The newest test and it is only available for dogs. A single fecal sample is needed although sometimes normal dogs will test negative for Elastase. This means that EPI can be ruled out when the Elastase test is positive but not confirmed when the Elastase test is negative.

What is the Prognosis?

Treatment of EPI is usually necessary for life. Most dogs with EPI due to pancreatic acinar atrophy respond well to enzyme replacement alone, and have a good long-term prognosis. While dogs who have suffered weight loss do not always regain it, most of them will no longer continue to lose weight. Animals requiring additional medications to boost the effectiveness of enzyme therapy generally do well. In cats and in older dogs with EPI due to chronic pancreatitis, the outcome is much less predictable. If other conditions are present, particularly diabetes mellitus, then the prognosis may depend more on the ability to treat these complicating factors successfully.

What is the Treatment?

While there is no cure or any preventatives for EPI, there are some treatments available.

Enzyme replacementsDiarrhea will begin to resolve in a few days, followed by gradual weight gain in most dogs.

Augment enzyme replacement therapy For pets who do not respond appropriately to enzyme replacement alone. Certain drugs that block H-2 receptors in the stomach that may increase enzyme replacement effectiveness by preventing breakdown of the enzymes in the stomach.

A low fat, low fiber, highly digestible diet Oral vitamin E supplementation or intra muscular injections of vitamin B-12 may be administered to restore serum concentrations of these substances in dogs with EPI. Dietary supplementation with digestive enzymes is effective even though most of the supplement given is digested in the stomach along with other dietary proteins. The little bit that survives the acid bath of the stomach and its own protein-digesting chemicals turns out to be enough to stop the diarrhea and enable the patient to actually gain some weight.

The Good News

A response to therapy is generally seen within a week of beginning therapy. Response can be excellent, however, about one in 5 dogs will simply not respond well. Many never regain a normal weight.